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manual_slop/docs/guide_architecture.md
2026-03-08 01:46:34 -05:00

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# Architecture
[Top](../README.md) | [Tools & IPC](guide_tools.md) | [MMA Orchestration](guide_mma.md) | [Simulations](guide_simulations.md)
---
## Philosophy: The Decoupled State Machine
Manual Slop solves a single tension: **AI reasoning is high-latency and non-deterministic; GUI interaction must be low-latency and responsive.** The engine enforces strict decoupling between four thread domains so that multi-second LLM calls never block the render loop, and every AI-generated payload passes through a human-auditable gate before execution.
The architectural philosophy follows data-oriented design principles:
- The GUI (`gui_2.py`, `app_controller.py`) remains a pure visualization of application state
- State mutations occur only through lock-guarded queues consumed on the main render thread
- Background threads never write GUI state directly — they serialize task dicts for later consumption
- All cross-thread communication uses explicit synchronization primitives (Locks, Conditions, Events)
## Project Structure
The codebase is organized into a `src/` layout to separate implementation from configuration and artifacts.
```
manual_slop/
├── conductor/ # Conductor tracks, specs, and plans
├── docs/ # Deep-dive architectural documentation
├── logs/ # Session logs, agent traces, and errors
├── scripts/ # Build, migration, and IPC bridge scripts
├── src/ # Core Python implementation
│ ├── ai_client.py # LLM provider abstraction
│ ├── gui_2.py # Main ImGui application
│ ├── mcp_client.py # MCP tool implementation
│ └── ... # Other core modules
├── tests/ # Pytest suite and simulation fixtures
├── simulation/ # Workflow and agent simulation logic
├── sloppy.py # Primary application entry point
├── config.toml # Global application settings
└── manual_slop.toml # Project-specific configuration
```
---
## Thread Domains
Four distinct thread domains operate concurrently:
| Domain | Created By | Purpose | Lifecycle | Key Synchronization Primitives |
|---|---|---|---|---|
| **Main / GUI** | `immapp.run()` | Dear ImGui retained-mode render loop; sole writer of GUI state | App lifetime | None (consumer of queues) |
| **Asyncio Worker** | `App.__init__` via `threading.Thread(daemon=True)` | Event queue processing, AI client calls | Daemon (dies with process) | `AsyncEventQueue`, `threading.Lock` |
| **HookServer** | `api_hooks.HookServer.start()` | HTTP API on `:8999` for external automation and IPC | Daemon thread | `threading.Lock`, `threading.Event` |
| **Ad-hoc** | Transient `threading.Thread` calls | Model-fetching, legacy send paths, log pruning | Short-lived | Task-specific locks |
The asyncio worker is **not** the main thread's event loop. It runs a dedicated `asyncio.new_event_loop()` on its own daemon thread:
```python
# AppController.__init__:
self._loop = asyncio.new_event_loop()
self._loop_thread = threading.Thread(target=self._run_event_loop, daemon=True)
self._loop_thread.start()
# _run_event_loop:
def _run_event_loop(self) -> None:
asyncio.set_event_loop(self._loop)
self._loop.create_task(self._process_event_queue())
self._loop.run_forever()
```
The GUI thread uses `asyncio.run_coroutine_threadsafe(coro, self._loop)` to push work into this loop.
### Thread-Local Context Isolation
For concurrent multi-agent execution, the application uses `threading.local()` to manage per-thread context:
```python
# ai_client.py
_local_storage = threading.local()
def get_current_tier() -> Optional[str]:
"""Returns the current tier from thread-local storage."""
return getattr(_local_storage, "current_tier", None)
def set_current_tier(tier: Optional[str]) -> None:
"""Sets the current tier in thread-local storage."""
_local_storage.current_tier = tier
```
This ensures that comms log entries and tool calls are correctly tagged with their source tier even when multiple workers execute concurrently.
---
## Cross-Thread Data Structures
All cross-thread communication uses one of three patterns:
### Pattern A: AsyncEventQueue (GUI -> Asyncio)
```python
# events.py
class AsyncEventQueue:
_queue: asyncio.Queue # holds Tuple[str, Any] items
async def put(self, event_name: str, payload: Any = None) -> None
async def get(self) -> Tuple[str, Any]
```
The central event bus. Uses `asyncio.Queue`, so non-asyncio threads must enqueue via `asyncio.run_coroutine_threadsafe()`. Consumer is `App._process_event_queue()`, running as a long-lived coroutine on the asyncio loop.
### Pattern B: Guarded Lists (Any Thread -> GUI)
Background threads cannot write GUI state directly. They append task dicts to lock-guarded lists; the main thread drains these once per frame:
```python
# App.__init__:
self._pending_gui_tasks: list[dict[str, Any]] = []
self._pending_gui_tasks_lock = threading.Lock()
self._pending_comms: list[dict[str, Any]] = []
self._pending_comms_lock = threading.Lock()
self._pending_tool_calls: list[tuple[str, str, float]] = []
self._pending_tool_calls_lock = threading.Lock()
self._pending_history_adds: list[dict[str, Any]] = []
self._pending_history_adds_lock = threading.Lock()
```
Additional locks:
```python
self._send_thread_lock = threading.Lock() # Guards send_thread creation
self._pending_dialog_lock = threading.Lock() # Guards _pending_dialog + _pending_actions dict
```
### Pattern C: Condition-Variable Dialogs (Bidirectional Blocking)
Used for Human-in-the-Loop (HITL) approval. Background thread blocks on `threading.Condition`; GUI thread signals after user action. See the [HITL section](#the-execution-clutch-human-in-the-loop) below.
---
## Event System
Three classes in `events.py` (89 lines, no external dependencies beyond `asyncio` and `typing`):
### EventEmitter
```python
class EventEmitter:
_listeners: Dict[str, List[Callable]]
def on(self, event_name: str, callback: Callable) -> None
def emit(self, event_name: str, *args: Any, **kwargs: Any) -> None
```
Synchronous pub-sub. Callbacks execute in the caller's thread. Used by `ai_client.events` for lifecycle hooks (`request_start`, `response_received`, `tool_execution`). No thread safety — relies on consistent single-thread usage.
### AsyncEventQueue
Described above in Pattern A.
### UserRequestEvent
```python
class UserRequestEvent:
prompt: str # User's raw input text
stable_md: str # Generated markdown context (files, screenshots)
file_items: List[Any] # File attachment items for dynamic refresh
disc_text: str # Serialized discussion history
base_dir: str # Working directory for shell commands
def to_dict(self) -> Dict[str, Any]
```
Pure data carrier. Created on the GUI thread in `_handle_generate_send`, consumed on the asyncio thread in `_handle_request_event`.
---
## Application Lifetime
### Boot Sequence
The `App.__init__` (lines 152-296) follows this precise order:
1. **Config hydration**: Reads `config.toml` (global) and `<project>.toml` (local). Builds the initial "world view" — tracked files, discussion history, active models.
2. **Thread bootstrapping**:
- Asyncio event loop thread starts (`_loop_thread`).
- `HookServer` starts as a daemon if `test_hooks_enabled` or provider is `gemini_cli`.
3. **Callback wiring** (`_init_ai_and_hooks`): Connects `ai_client.confirm_and_run_callback`, `comms_log_callback`, `tool_log_callback` to GUI handlers.
4. **UI entry**: Main thread enters `immapp.run()`. GUI is now alive; background threads are ready.
### Shutdown Sequence
When `immapp.run()` returns (user closed window):
1. `hook_server.stop()` — shuts down HTTP server, joins thread.
2. `perf_monitor.stop()`.
3. `ai_client.cleanup()` — destroys server-side API caches (Gemini `CachedContent`).
4. **Dual-Flush persistence**: `_flush_to_project()`, `_save_active_project()`, `_flush_to_config()`, `save_config()` — commits state back to both project and global configs.
5. `session_logger.close_session()`.
The asyncio loop thread is a daemon — it dies with the process. `App.shutdown()` exists for explicit cleanup in test scenarios:
```python
def shutdown(self) -> None:
if self._loop.is_running():
self._loop.call_soon_threadsafe(self._loop.stop)
if self._loop_thread.is_alive():
self._loop_thread.join(timeout=2.0)
```
---
## The Task Pipeline: Producer-Consumer Synchronization
### Request Flow
```
GUI Thread Asyncio Thread GUI Thread (next frame)
────────── ────────────── ──────────────────────
1. User clicks "Gen + Send"
2. _handle_generate_send():
- Compiles md context
- Creates UserRequestEvent
- Enqueues via
run_coroutine_threadsafe ──> 3. _process_event_queue():
awaits event_queue.get()
routes "user_request" to
_handle_request_event()
4. Configures ai_client
5. ai_client.send() BLOCKS
(seconds to minutes)
6. On completion, enqueues
"response" event back ──> 7. _process_pending_gui_tasks():
Drains task list under lock
Sets ai_response text
Triggers terminal blink
```
### Event Types Routed by `_process_event_queue`
| Event Name | Action |
|---|---|
| `"user_request"` | Calls `_handle_request_event(payload)` — synchronous blocking AI call |
| `"response"` | Appends `{"action": "handle_ai_response", ...}` to `_pending_gui_tasks` |
| `"mma_state_update"` | Appends `{"action": "mma_state_update", ...}` to `_pending_gui_tasks` |
| `"mma_spawn_approval"` | Appends the raw payload for HITL dialog creation |
| `"mma_step_approval"` | Appends the raw payload for HITL dialog creation |
The pattern: events arriving on the asyncio thread that need GUI state changes are **serialized into `_pending_gui_tasks`** for consumption on the next render frame.
### Frame-Sync Mechanism: `_process_pending_gui_tasks`
Called once per ImGui frame on the **main GUI thread**. This is the sole safe point for mutating GUI-visible state.
**Locking strategy** — copy-and-clear:
```python
def _process_pending_gui_tasks(self) -> None:
if not self._pending_gui_tasks:
return
with self._pending_gui_tasks_lock:
tasks = self._pending_gui_tasks[:] # Snapshot
self._pending_gui_tasks.clear() # Release lock fast
for task in tasks:
# Process each task outside the lock
```
Acquires the lock briefly to snapshot the task list, then processes outside the lock. Minimizes lock contention with producer threads.
### Complete Action Type Catalog
| Action | Source | Effect |
|---|---|---|
| `"refresh_api_metrics"` | asyncio/hooks | Updates API metrics display |
| `"handle_ai_response"` | asyncio | Sets `ai_response`, `ai_status`, `mma_streams[stream_id]`; triggers blink; optionally auto-adds to discussion history |
| `"show_track_proposal"` | asyncio | Sets `proposed_tracks` list, opens modal |
| `"mma_state_update"` | asyncio | Updates `mma_status`, `active_tier`, `mma_tier_usage`, `active_tickets`, `active_track` |
| `"set_value"` | HookServer | Sets any field in `_settable_fields` map via `setattr`; special-cases `current_provider`/`current_model` to reconfigure AI client |
| `"click"` | HookServer | Dispatches to `_clickable_actions` map; introspects signatures to decide whether to pass `user_data` |
| `"select_list_item"` | HookServer | Routes to `_switch_discussion()` for discussion listbox |
| `{"type": "ask"}` | HookServer | Opens ask dialog: sets `_pending_ask_dialog = True`, stores `_ask_request_id` and `_ask_tool_data` |
| `"clear_ask"` | HookServer | Clears ask dialog state if request_id matches |
| `"custom_callback"` | HookServer | Executes an arbitrary callable with args |
| `"mma_step_approval"` | asyncio (MMA engine) | Creates `MMAApprovalDialog`, stores in `_pending_mma_approval` |
| `"mma_spawn_approval"` | asyncio (MMA engine) | Creates `MMASpawnApprovalDialog`, stores in `_pending_mma_spawn` |
| `"refresh_from_project"` | HookServer/internal | Reloads all UI state from project dict |
---
## The Execution Clutch: Human-in-the-Loop
The "Execution Clutch" ensures every destructive AI action passes through an auditable human gate. Three dialog types implement this, all sharing the same blocking pattern.
### Dialog Classes
**`ConfirmDialog`** — PowerShell script execution approval:
```python
class ConfirmDialog:
_uid: str # uuid4 identifier
_script: str # The PowerShell script text (editable)
_base_dir: str # Working directory
_condition: threading.Condition # Blocking primitive
_done: bool # Signal flag
_approved: bool # User's decision
def wait(self) -> tuple[bool, str] # Blocks until _done; returns (approved, script)
```
**`MMAApprovalDialog`** — MMA tier step approval:
```python
class MMAApprovalDialog:
_ticket_id: str
_payload: str # The step payload (editable)
_condition: threading.Condition
_done: bool
_approved: bool
def wait(self) -> tuple[bool, str] # Returns (approved, payload)
```
**`MMASpawnApprovalDialog`** — Sub-agent spawn approval:
```python
class MMASpawnApprovalDialog:
_ticket_id: str
_role: str # tier3-worker, tier4-qa, etc.
_prompt: str # Spawn prompt (editable)
_context_md: str # Context document (editable)
_condition: threading.Condition
_done: bool
_approved: bool
_abort: bool # Can abort entire track
def wait(self) -> dict[str, Any] # Returns {approved, abort, prompt, context_md}
```
### Blocking Flow
Using `ConfirmDialog` as exemplar:
```
ASYNCIO THREAD (ai_client tool callback) GUI MAIN THREAD
───────────────────────────────────────── ───────────────
1. ai_client calls _confirm_and_run(script)
2. Creates ConfirmDialog(script, base_dir)
3. Stores dialog:
- Headless: _pending_actions[uid] = dialog
- GUI mode: _pending_dialog = dialog
4. If test_hooks_enabled:
pushes to _api_event_queue
5. dialog.wait() BLOCKS on _condition
6. Next frame: ImGui renders
_pending_dialog in modal
7. User clicks Approve/Reject
8. _handle_approve_script():
with dialog._condition:
dialog._approved = True
dialog._done = True
dialog._condition.notify_all()
9. wait() returns (True, potentially_edited_script)
10. Executes shell_runner.run_powershell()
11. Returns output to ai_client
```
The `_condition.wait(timeout=0.1)` uses a 100ms polling interval inside a loop — a polling-with-condition hybrid that ensures the blocking thread wakes periodically.
### Resolution Paths
**GUI button path** (normal interactive use):
`_handle_approve_script()` / `_handle_approve_mma_step()` / `_handle_approve_spawn()` directly manipulate the dialog's condition variable from the GUI thread.
**HTTP API path** (headless/automation):
`resolve_pending_action(action_id, approved)` looks up the dialog by UUID in `_pending_actions` dict (headless) or `_pending_dialog` (GUI), then signals the condition:
```python
def resolve_pending_action(self, action_id: str, approved: bool) -> bool:
with self._pending_dialog_lock:
if action_id in self._pending_actions:
dialog = self._pending_actions[action_id]
with dialog._condition:
dialog._approved = approved
dialog._done = True
dialog._condition.notify_all()
return True
```
**MMA approval path**:
`_handle_mma_respond(approved, payload, abort, prompt, context_md)` is the unified resolver. It uses a `dialog_container` — a one-element list `[None]` used as a mutable reference shared between the MMA engine (which creates the container) and the GUI (which populates it via `_process_pending_gui_tasks`).
---
## AI Client: Multi-Provider Architecture
`ai_client.py` operates as a **stateful singleton** — all provider state is held in module-level globals. There is no class wrapping; the module itself is the abstraction layer.
### Module-Level State
```python
_provider: str = "gemini" # "gemini" | "anthropic" | "deepseek" | "gemini_cli"
_model: str = "gemini-2.5-flash-lite"
_temperature: float = 0.0
_max_tokens: int = 8192
_history_trunc_limit: int = 8000 # Char limit for truncating old tool outputs
_send_lock: threading.Lock # Serializes ALL send() calls across providers
```
Per-provider client objects:
```python
# Gemini (SDK-managed stateful chat)
_gemini_client: genai.Client | None
_gemini_chat: Any # Holds history internally
_gemini_cache: Any # Server-side CachedContent
_gemini_cache_md_hash: int | None # For cache invalidation
_GEMINI_CACHE_TTL: int = 3600 # 1-hour; rebuilt at 90% (3240s)
# Anthropic (client-managed history)
_anthropic_client: anthropic.Anthropic | None
_anthropic_history: list[dict] # Mutable [{role, content}, ...]
_anthropic_history_lock: threading.Lock
# DeepSeek (raw HTTP, client-managed history)
_deepseek_history: list[dict]
_deepseek_history_lock: threading.Lock
# Gemini CLI (adapter wrapper)
_gemini_cli_adapter: GeminiCliAdapter | None
```
Safety limits:
```python
MAX_TOOL_ROUNDS: int = 10 # Max tool-call loop iterations per send()
_MAX_TOOL_OUTPUT_BYTES: int = 500_000 # 500KB cumulative tool output budget
_ANTHROPIC_CHUNK_SIZE: int = 120_000 # Max chars per system text block
_ANTHROPIC_MAX_PROMPT_TOKENS: int = 180_000 # 200k limit minus headroom
_GEMINI_MAX_INPUT_TOKENS: int = 900_000 # 1M window minus headroom
```
### The `send()` Dispatcher
```python
def send(md_content, user_message, base_dir=".", file_items=None,
discussion_history="", stream=False,
pre_tool_callback=None, qa_callback=None) -> str:
with _send_lock:
if _provider == "gemini": return _send_gemini(...)
elif _provider == "gemini_cli": return _send_gemini_cli(...)
elif _provider == "anthropic": return _send_anthropic(...)
elif _provider == "deepseek": return _send_deepseek(..., stream=stream)
```
`_send_lock` serializes all API calls — only one provider call can be in-flight at a time. All providers share the same callback signatures. Return type is always `str`.
### Provider Comparison
| Aspect | Gemini SDK | Anthropic | DeepSeek | Gemini CLI |
|---|---|---|---|---|
| **Client** | `genai.Client` | `anthropic.Anthropic` | Raw `requests.post` | `GeminiCliAdapter` (subprocess) |
| **History** | SDK-managed (`_gemini_chat._history`) | Client-managed list | Client-managed list | CLI-managed (session ID) |
| **Caching** | Server-side `CachedContent` with TTL | Prompt caching via `cache_control: ephemeral` (4 breakpoints) | None | None |
| **Tool format** | `types.FunctionDeclaration` | JSON Schema dict | Not declared | Same as SDK via adapter |
| **Tool results** | `Part.from_function_response(response={"output": ...})` | `{"type": "tool_result", "tool_use_id": ..., "content": ...}` | `{"role": "tool", "tool_call_id": ..., "content": ...}` | `{"role": "tool", ...}` |
| **History trimming** | In-place at 40% of 900K token estimate | 2-phase: strip stale file refreshes, then drop turn pairs at 180K | None | None |
| **Streaming** | No | No | Yes | No |
### Tool-Call Loop (common pattern across providers)
All providers follow the same high-level loop, iterated up to `MAX_TOOL_ROUNDS + 2` times:
1. Send message (or tool results from prior round) to API.
2. Extract text response and any function calls.
3. Log to comms log; emit events.
4. If no function calls or max rounds exceeded: **break**.
5. For each function call:
- If `pre_tool_callback` rejects: return rejection text.
- Dispatch to `mcp_client.dispatch()` or `shell_runner.run_powershell()`.
- After the **last** call of this round: run `_reread_file_items()` for context refresh.
- Truncate tool output at `_history_trunc_limit` chars.
- Accumulate `_cumulative_tool_bytes`.
6. If cumulative bytes > 500KB: inject warning.
7. Package tool results in provider-specific format; loop.
### Context Refresh Mechanism
After the last tool call in each round, `_reread_file_items(file_items)` checks mtimes of all tracked files:
1. For each file item: compare `Path.stat().st_mtime` against stored `mtime`.
2. If unchanged: pass through as-is.
3. If changed: re-read content, store `old_content` for diffing, update `mtime`.
4. Changed files are diffed via `_build_file_diff_text`:
- Files <= 200 lines: emit full content.
- Files > 200 lines with `old_content`: emit `difflib.unified_diff`.
5. Diff is appended to the last tool's output as `[SYSTEM: FILES UPDATED]\n\n{diff}`.
6. Stale `[FILES UPDATED]` blocks are stripped from older history turns by `_strip_stale_file_refreshes` to prevent context bloat.
### Anthropic Cache Strategy (4-Breakpoint System)
Anthropic allows a maximum of 4 `cache_control: ephemeral` breakpoints:
| # | Location | Purpose |
|---|---|---|
| 1 | Last block of stable system prompt | Cache base instructions |
| 2 | Last block of context chunks | Cache file context |
| 3 | Last tool definition | Cache tool schema |
| 4 | Second-to-last user message | Cache conversation prefix |
Before placing breakpoint 4, all existing `cache_control` is stripped from history to prevent exceeding the limit.
### Gemini Cache Strategy (Server-Side TTL)
System instruction content is hashed. On each call, a 3-way decision:
- **Hash changed**: Delete old cache, rebuild with new content.
- **Cache age > 90% of TTL**: Proactive renewal (delete + rebuild).
- **No cache exists**: Create new `CachedContent` if token count >= 2048; otherwise inline.
---
## Comms Log System
Every API interaction is logged to a module-level list with real-time GUI push:
```python
def _append_comms(direction: str, kind: str, payload: dict[str, Any]) -> None:
entry = {
"ts": datetime.now().strftime("%H:%M:%S"),
"direction": direction, # "OUT" (to API) or "IN" (from API)
"kind": kind, # "request" | "response" | "tool_call" | "tool_result"
"provider": _provider,
"model": _model,
"payload": payload,
}
_comms_log.append(entry)
if comms_log_callback:
comms_log_callback(entry) # Real-time push to GUI
```
---
## State Machines
### `ai_status` (Informal)
```
"idle" -> "sending..." -> [AI call in progress]
-> "running powershell..." -> "powershell done, awaiting AI..."
-> "fetching url..." | "searching web..."
-> "done" | "error"
-> "idle" (on reset)
```
### HITL Dialog State (Binary per type)
- `_pending_dialog is not None` — script confirmation active
- `_pending_mma_approval is not None` — MMA step approval active
- `_pending_mma_spawn is not None` — spawn approval active
- `_pending_ask_dialog == True` — tool ask dialog active
---
## Security: The MCP Allowlist
Every filesystem tool (read, list, search, write) is gated by the MCP Bridge (`mcp_client.py`). See [guide_tools.md](guide_tools.md) for the complete security model, tool inventory, and endpoint reference.
Summary: Every path is resolved to an absolute path and checked against a dynamically-built allowlist constructed from the project's tracked files and base directories. Files named `history.toml` or `*_history.toml` are hard-blacklisted.
---
## Telemetry & Auditing
Every interaction is designed to be auditable:
- **JSON-L Comms Logs**: Raw API traffic logged to `logs/sessions/<id>/comms.log` for debugging and token cost analysis.
- **Tool Call Logs**: Markdown-formatted sequential records to `toolcalls.log`.
- **Generated Scripts**: Every PowerShell script that passes through the Execution Clutch is saved to `scripts/generated/<ts>_<seq>.ps1`.
- **API Hook Logs**: All HTTP hook invocations logged to `apihooks.log`.
- **CLI Call Logs**: Subprocess execution details (command, stdin, stdout, stderr, latency) to `clicalls.log` as JSON-L.
- **Performance Monitor**: Real-time FPS, Frame Time, CPU, Input Lag tracked and queryable via Hook API.
### Telemetry Data Structures
```python
# Comms log entry (JSON-L)
{
"ts": "14:32:05",
"direction": "OUT",
"kind": "tool_call",
"provider": "gemini",
"model": "gemini-2.5-flash-lite",
"payload": {
"name": "run_powershell",
"id": "call_abc123",
"script": "Get-ChildItem"
},
"source_tier": "Tier 3",
"local_ts": 1709875925.123
}
# Performance metrics (via get_metrics())
{
"fps": 60.0,
"fps_avg": 58.5,
"last_frame_time_ms": 16.67,
"frame_time_ms_avg": 17.1,
"cpu_percent": 12.5,
"cpu_percent_avg": 15.2,
"input_lag_ms": 2.3,
"input_lag_ms_avg": 3.1,
"time_render_mma_dashboard_ms": 5.2,
"time_render_mma_dashboard_ms_avg": 4.8
}
```
---
## MMA Engine Architecture
### WorkerPool: Concurrent Worker Management
The `WorkerPool` class in `multi_agent_conductor.py` manages a bounded pool of worker threads:
```python
class WorkerPool:
def __init__(self, max_workers: int = 4):
self.max_workers = max_workers
self._active: dict[str, threading.Thread] = {}
self._lock = threading.Lock()
self._semaphore = threading.Semaphore(max_workers)
def spawn(self, ticket_id: str, target: Callable, args: tuple) -> Optional[threading.Thread]:
with self._lock:
if len(self._active) >= self.max_workers:
return None
def wrapper(*a, **kw):
try:
with self._semaphore:
target(*a, **kw)
finally:
with self._lock:
self._active.pop(ticket_id, None)
t = threading.Thread(target=wrapper, args=args, daemon=True)
with self._lock:
self._active[ticket_id] = t
t.start()
return t
```
**Key behaviors**:
- **Bounded concurrency**: `max_workers` (default 4) limits parallel ticket execution
- **Semaphore gating**: Ensures no more than `max_workers` can execute simultaneously
- **Automatic cleanup**: Thread removes itself from `_active` dict on completion
- **Non-blocking spawn**: Returns `None` if pool is full, allowing the engine to defer
### ConductorEngine: Orchestration Loop
The `ConductorEngine` orchestrates ticket execution within a track:
```python
class ConductorEngine:
def __init__(self, track: Track, event_queue: Optional[SyncEventQueue] = None,
auto_queue: bool = False) -> None:
self.track = track
self.event_queue = event_queue
self.dag = TrackDAG(self.track.tickets)
self.engine = ExecutionEngine(self.dag, auto_queue=auto_queue)
self.pool = WorkerPool(max_workers=4)
self._abort_events: dict[str, threading.Event] = {}
self._pause_event = threading.Event()
self._tier_usage_lock = threading.Lock()
self.tier_usage = {
"Tier 1": {"input": 0, "output": 0, "model": "gemini-3.1-pro-preview"},
"Tier 2": {"input": 0, "output": 0, "model": "gemini-3-flash-preview"},
"Tier 3": {"input": 0, "output": 0, "model": "gemini-2.5-flash-lite"},
"Tier 4": {"input": 0, "output": 0, "model": "gemini-2.5-flash-lite"},
}
```
**Main execution loop** (`run` method):
1. **Pause check**: If `_pause_event` is set, sleep and broadcast "paused" status
2. **DAG tick**: Call `engine.tick()` to get ready tasks
3. **Completion check**: If no ready tasks and all completed, break with "done" status
4. **Wait for workers**: If tasks in-progress or pool active, sleep and continue
5. **Blockage detection**: If no ready, no in-progress, and not all done, break with "blocked" status
6. **Spawn workers**: For each ready task, spawn a worker via `pool.spawn()`
7. **Model escalation**: Workers use `models_list[min(retry_count, 2)]` for capability upgrade on retries
### Abort Event Propagation
Each ticket has an associated `threading.Event` for abort signaling:
```python
# Before spawning worker
self._abort_events[ticket.id] = threading.Event()
# Worker checks abort at three points:
# 1. Before major work
if abort_event.is_set():
ticket.status = "killed"
return "ABORTED"
# 2. Before tool execution (in clutch_callback)
if abort_event.is_set():
return False # Reject tool
# 3. After blocking send() returns
if abort_event.is_set():
ticket.status = "killed"
return "ABORTED"
```
---
## Architectural Invariants
1. **Single-writer principle**: All GUI state mutations happen on the main thread via `_process_pending_gui_tasks`. Background threads never write GUI state directly.
2. **Copy-and-clear lock pattern**: `_process_pending_gui_tasks` snapshots and clears the task list under the lock, then processes outside the lock.
3. **Context Amnesia**: Each MMA Tier 3 Worker starts with `ai_client.reset_session()`. No conversational bleed between tickets.
4. **Send serialization**: `_send_lock` ensures only one provider call is in-flight at a time across all threads.
5. **Dual-Flush persistence**: On exit, state is committed to both project-level and global-level config files.
6. **No cross-thread GUI mutation**: Background threads must push tasks to `_pending_gui_tasks` rather than calling GUI methods directly.
7. **Abort-before-execution**: Workers check abort events before major work phases, enabling clean cancellation.
8. **Bounded worker pool**: `WorkerPool` enforces `max_workers` limit to prevent resource exhaustion.
---
## Error Classification & Recovery
### ProviderError Taxonomy
The `ProviderError` class provides structured error classification:
```python
class ProviderError(Exception):
def __init__(self, kind: str, provider: str, original: Exception):
self.kind = kind # "quota" | "rate_limit" | "auth" | "balance" | "network" | "unknown"
self.provider = provider
self.original = original
def ui_message(self) -> str:
labels = {
"quota": "QUOTA EXHAUSTED",
"rate_limit": "RATE LIMITED",
"auth": "AUTH / API KEY ERROR",
"balance": "BALANCE / BILLING ERROR",
"network": "NETWORK / CONNECTION ERROR",
"unknown": "API ERROR",
}
return f"[{self.provider.upper()} {labels.get(self.kind, 'API ERROR')}]\n\n{self.original}"
```
### Error Recovery Patterns
| Error Kind | Recovery Strategy |
|---|---|
| `quota` | Display in UI, await user intervention |
| `rate_limit` | Exponential backoff (not yet implemented) |
| `auth` | Prompt for credential verification |
| `balance` | Display billing alert |
| `network` | Auto-retry with timeout |
| `unknown` | Log full traceback, display in UI |
---
## Memory Management
### History Trimming Strategies
**Gemini (40% threshold)**:
```python
if total_in > _GEMINI_MAX_INPUT_TOKENS * 0.4:
while len(hist) > 4 and total_in > _GEMINI_MAX_INPUT_TOKENS * 0.3:
# Drop oldest message pairs
hist.pop(0) # Assistant
hist.pop(0) # User
```
**Anthropic (180K limit)**:
```python
def _trim_anthropic_history(system_blocks, history):
est = _estimate_prompt_tokens(system_blocks, history)
while len(history) > 3 and est > _ANTHROPIC_MAX_PROMPT_TOKENS:
# Drop turn pairs, preserving tool_result chains
...
```
### Tool Output Budget
```python
_MAX_TOOL_OUTPUT_BYTES: int = 500_000 # 500KB cumulative
if _cumulative_tool_bytes > _MAX_TOOL_OUTPUT_BYTES:
# Inject warning, force final answer
parts.append("SYSTEM WARNING: Cumulative tool output exceeded 500KB budget.")
```
### AST Cache (file_cache.py)
```python
_ast_cache: Dict[str, Tuple[float, tree_sitter.Tree]] = {}
def get_cached_tree(self, path: Optional[str], code: str) -> tree_sitter.Tree:
mtime = p.stat().st_mtime if p.exists() else 0.0
if path in _ast_cache:
cached_mtime, tree = _ast_cache[path]
if cached_mtime == mtime:
return tree
# Parse and cache with simple LRU (max 10 entries)
if len(_ast_cache) >= 10:
del _ast_cache[next(iter(_ast_cache))]
tree = self.parse(code)
_ast_cache[path] = (mtime, tree)
return tree
```